Growth enhancement and control of bacterial and fungal plant diseases with streptomyces scopuliridis

Abstract

Methods of controlling plant diseases mediated by bacterial or fungal plant pathogens. The method comprises providing Streptomyces scopuliridis strain RB72 or an isolated protein or polypeptide comprising the amino acid of SEQ ID NO:1 and applying the Streptomyces scopuliridis strain RB72 or the isolated protein or polypeptide comprising the amino acid of SEQ ID NO:1 to plants or plant seeds under conditions effective to treat plant diseases mediated by bacterial or fungal plant pathogens. Also disclosed is a plant or plant seed treated by this method, a planting composition, and a method of enhancing growth.

Description

[0001]This application claims benefit of U.S. Provisional Patent Application Ser. No. 61 / 369,315, filed Jul. 30, 2010.FIELD OF THE INVENTION[0002]The present invention relates to the enhancement of growth and the control of plant diseases caused by bacterial and fungal pathogens with a newly described species of bacterium, Streptomyces scopuliridis. BACKGROUND OF THE INVENTION[0003]Plants are under almost constant attack by bacterial and fungal pathogens in the environment and economic losses are a frequent consequence of this assault. To avoid or reduce economic loss, synthetic chemical fungicides have been traditionally used to keep the development of disease in check. However, the impact of chemical pesticides on the environment and human health can be harmful; this impact has been well-documented. Improperly used chemical pesticides can contaminate water, air, and soil and can have lasting harmful effects on aquatic life, birds, mammals, and beneficial insects such as bees. Furt...

AI Technical Summary

Benefits of technology

The present invention provides a method for controlling plant diseases caused by bacterial or fungal pathogens using a new biocontrol agent called Streptomyces scopuliridis strain RB72 or an isolated protein or polypeptide containing its amino acid sequence. The method involves applying the strain or its protein to plants or plant seeds to treat the disease. The invention also provides a pathogen-resistant plant or plant seed that has been treated with the strain or its protein. Additionally, the invention provides a planting composition that includes the strain or its protein in growing media for planting. Finally, the invention provides a method for enhancing plant growth by applying the strain or its protein to plants or plant seeds. The invention offers a safe alternative to chemical pesticides and can be used in both agricultural and horticultural crops.

Problems solved by technology

Plants are under almost constant attack by bacterial and fungal pathogens in the environment and economic losses are a frequent consequence of this assault.

However, the impact of chemical pesticides on the environment and human health can be harmful; this impact has been well-documented.

Improperly used chemical pesticides can contaminate water, air, and soil and can have lasting harmful effects on aquatic life, birds, mammals, and beneficial insects such as bees.

Typically, plant diseases caused by Phytophthora are very difficult to control and often lead to the death of the plant.

This pathogen is widespread and an economic problem to growers around the world.

Attempts to manage Phytophthora spp. with techniques such as rootstock selection and site modification have been mostly unreliable.

Pythium damping off is a very common problem in fields and greenhouses where the organism kills newly emerged seedlings (Jarvis, W. R., “Managing Diseases in Greenhouse Crops,” APS Press, St.

For this reason, Pythium spp. are more devastating to commercial crop production because crop rotation alone will often not eradicate the pathogen (nor will fallowing the field, since Pythium spp. are also good saprotrophs, and will survive for long periods of time on decaying plant matter).

However, there are a number of important Fusarium species that are pathogenic to agricultural crops.

Fusarium contamination in barley can result in head blight and, in extreme contaminations, the barley can appear pink.

Fusarium graminearum can also cause root rot and seedling blight.

Diseases caused by Fusarium spp. can be economically devastating.

Rhizoctonia spp. usually attack plants at the soil line, causing root loss and constriction of the stem which results in girdling and death of the tops.

This pathogen can attack leaves as well, and is especially severe when plants are grown close together and kept moist.

It is generally not a fatal disease, but can cause leaf curling and yellowing, stunting of the host plant and defoliation.

It is particularly detrimental to ornamental plants, significantly decreasing their value and marketability due to unsightly symptoms.

Downy mildew is a broad category of diseases that can appear on many host plants and is particularly devastating on crucifers, grapes, hops, and many vegetable crops.

Infected plant parts eventually become brown and necrotic and can die.

Botrytis infections are favored by cool, rainy conditions—this disease is particularly damaging when rainy, drizzly weather continues over a period of several days.

Bacterial diseases of plants occur in almost every environment and can be extremely destructive.

In general, chemical sprays for bacterial diseases are less reliable than for most fungal diseases.

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